/* 课程详情页面样式 */
.course-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

/* 课程头部样式 */
.course-header {
    background: #f8f9fa;
    padding: 30px;
    border-radius: 8px;
    margin-bottom: 30px;
}

.course-info h1 {
    font-size: 28px;
    margin-bottom: 15px;
    color: #333;
}

.course-meta {
    display: flex;
    gap: 20px;
    color: #666;
    margin-bottom: 15px;
}

.course-meta span {
    display: flex;
    align-items: center;
    gap: 5px;
}

.course-meta i {
    font-size: 16px;
}

.description {
    color: #555;
    line-height: 1.6;
    margin-bottom: 20px;
}

.course-actions {
    display: flex;
    gap: 15px;
}

.btn-primary, .btn-secondary {
    padding: 10px 20px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-weight: 500;
    transition: all 0.3s ease;
}

.btn-primary {
    background: #007bff;
    color: white;
}

.btn-primary:hover {
    background: #0056b3;
}

.btn-secondary {
    background: white;
    color: #007bff;
    border: 1px solid #007bff;
}

.btn-secondary:hover {
    background: #f8f9fa;
}

/* 课程内容布局 */
.course-content {
    display: grid;
    grid-template-columns: 280px 1fr;
    gap: 30px;
}

/* 侧边栏样式 */
.course-sidebar {
    background: white;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.chapter-list {
    overflow-y: auto;
    max-height: calc(100vh - 300px);
}

.chapter-item {
    border-bottom: 1px solid #eee;
}

.chapter-header {
    padding: 15px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: #f8f9fa;
}

.chapter-header:hover {
    background: #e9ecef;
}

.chapter-content {
    display: none;
    padding: 10px 15px;
}

.chapter-content.active {
    display: block;
}

.lesson-item {
    padding: 10px 15px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 10px;
}

.lesson-item:hover {
    background: #f8f9fa;
}

.lesson-icon {
    width: 20px;
    height: 20px;
}

/* 内容主区域样式 */
.content-main {
    background: white;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    overflow: hidden;
}

/* 标签页样式 */
.content-tabs {
    display: flex;
    border-bottom: 1px solid #eee;
    background: #f8f9fa;
}

.tab-btn {
    padding: 15px 30px;
    border: none;
    background: none;
    cursor: pointer;
    font-weight: 500;
    color: #666;
    border-bottom: 2px solid transparent;
}

.tab-btn:hover {
    color: #007bff;
}

.tab-btn.active {
    color: #007bff;
    border-bottom-color: #007bff;
}

/* 内容显示区域 */
.tab-content {
    padding: 20px;
}

.tab-content.hidden {
    display: none;
}

/* 内容查看器样式 */
.content-viewer {
    min-height: 400px;
}

.video-player {
    width: 100%;
    aspect-ratio: 16/9;
    background: #000;
    margin-bottom: 20px;
}

.document-viewer {
    width: 100%;
    height: 600px;
    border: 1px solid #eee;
}

/* 讨论区样式 */
.discussion-area {
    margin-top: 20px;
}

.post-form {
    margin-bottom: 30px;
}

.post-form textarea {
    width: 100%;
    height: 100px;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 4px;
    margin-bottom: 10px;
    resize: vertical;
}

.discussion-list {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.discussion-item {
    border-bottom: 1px solid #eee;
    padding-bottom: 20px;
}

.discussion-header {
    display: flex;
    justify-content: space-between;
    margin-bottom: 10px;
}

.discussion-author {
    font-weight: 500;
}

.discussion-time {
    color: #666;
}

.discussion-content {
    color: #333;
    line-height: 1.6;
}

/* 笔记区域样式 */
.notes-area {
    margin-top: 20px;
}

.note-form {
    margin-bottom: 30px;
}

.note-form textarea {
    width: 100%;
    height: 150px;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 4px;
    margin-bottom: 10px;
    resize: vertical;
}

.note-list {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.note-item {
    background: #f8f9fa;
    padding: 15px;
    border-radius: 4px;
}

.note-time {
    color: #666;
    font-size: 14px;
    margin-bottom: 10px;
}

.note-content {
    color: #333;
    line-height: 1.6;
}

/* 响应式设计 */
@media (max-width: 992px) {
    .course-content {
        grid-template-columns: 1fr;
    }

    .course-sidebar {
        position: sticky;
        top: 20px;
    }
}

@media (max-width: 768px) {
    .course-meta {
        flex-wrap: wrap;
    }

    .content-tabs {
        flex-wrap: wrap;
    }

    .tab-btn {
        flex: 1;
        text-align: center;
        padding: 10px;
    }
}
